The invention relates to an apparatus for supplying a respiratory gas to a user or a patient having a respiratory system disease.
In treatments for respiratory system diseases such as pulmonary emphysema or chronic bronchitis, oxygen inhalation is known as one of the most effective treatments. In oxygen inhalation therapy, oxygen gas or oxygen enhanced gas is supplied as a respiratory gas to the user from respiratory gas source such as an oxygen cylinder through a nasal cannula. Relatively large oxygen cylinders are used as respiratory gas source in hospitals or in the houses of the patients. On she other hand, when the patient goes out of his or her house, a compact portable oxygen cylinder is used. High pressure respiratory gas, compressed to about 20 Mpa, is filled in the portable oxygen cylinder because of its small volume.
FIG. 17 is a schematic diagram of a respiratory gas supplying apparatus including a conventional portable oxygen cylinder. In FIG. 17, a shut-off valve 2 is mounted to an oxygen cylinder 1. A flow regulating valve 3 is connected to the shut-off valve 2. A demand regulator 5 is connected to the flow regulating valve 3 through a conduit 4. From the demand regulator 5, respiratory gas is supplied to a user through a nasal cannula 7. The prior art shown in FIG. 17 is an example which includes a shut-off valve and a flow regulating valve according to the CGA (Compressed Gas Association) 670 and the flow regulating valve 3 is clamped to the housing of the shut-off valve 2 by a clamp bolt (not shown) connected to a handle 3a. 
When the respiratory gas is consumed and pressure in the oxygen cylinder is reduced to a predetermined pressure level, this oxygen cylinder is replaced with a new one. At that time, the clamp bolt is loosened with the handle 3a rotated to remove the flow regulating valve 3 from the shut-off valve 2 on the oxygen cylinder 1. This work is bothersome to a user having a respiratory system disease.
The invention is directed to solve the above described problems of the prior art, and to provide a respiratory gas supplying apparatus which is improved to facilitate the replacement of the oxygen cylinder.
Further, the objective of the invention is to h provide a respiratory gas supplying apparatus which is improved to facilitate the attachment and detachment of the demand regulator to and from the oxygen cylinder.
According to the invention, there is provided an apparatus for supplying a respiratory gas to a respiratory airway of a patient. The apparatus includes a cylinder filled with a respiratory gas, a cart having an accommodating portion for disposing the cylinder, a shut-off valve attached to the cylinder, a flow regulating valve adapted to be attached to the shut-off valve, a conduit, attached to the flow regulating valve, for directing the respiratory gas to the respiratory airway of the patient, a coupler, integrally connected to the flow regulating valve, for coupling the flow regulating valve to the shut-off valve, and a linkage mechanism for disconnecting the coupler from the shut-off valve when the cylinder is detached from the cart.
Preferably, the accommodating portion includes a housing which can incline relative to the frame of the cart, a handle, rotatably secured to a wall Of the housing, for moving the housing relative to the frame of the cart, and the linkage mechanism is connected to the handle.
The flow regulating valve preferably has an inlet port for receiving the respiratory gas and an outlet port for discharging the respiratory gas to the conduit. The shut-off valve has a coupler mounting portion in the form of a column to which the coupler is mounted. The coupler mounting portion includes a peripheral groove extending along the outer surface and an outlet port which is adapted to be fluidly connected to the inlet port of the flow regulating valve when the coupler is mounted to the coupler mounting portion. The coupler includes an engaging claw which is adapted to engage the peripheral groove when the coupler is mounted to the coupler mounting portion and a releasing mechanism for disengaging the engaging claw from the peripheral groove when the coupler is detached from the coupler mounting portion. The linkage mechanism engages the releasing mechanism when the cylinder is mounted to the cart.
According to another feature of the invention, an apparatus for supplying a respiratory gas to a respiratory airway of a patient includes a cylinder filled with a respiratory gas, a cart having an accommodating portion for disposing the cylinder, a shut-off valve attached to the cylinder, a demand regulator adapted to be attached to the shut-off valve, a conduit, attached to the demand regulator, for directing the respiratory gas to the respiratory airway of the patient, a coupler, integrally connected to the demand regulator, for coupling the demand regulator to the shut-off valve, and a linkage mechanism for disconnecting the coupler from the shut-off valve when the cylinder is detached from the cart.
The demand regulator preferably has an inlet port for receiving the respiratory gas and an outlet port for discharging the respiratory gas to the conduit. The shut-off valve has a coupler mounting portion in the form of a column to which the coupler is mounted, the coupler mounting portion includes a peripheral groove extending along the outer surface and an outlet port which is adapted to be fluidly connected to the inlet port of the demand regulator when the coupler is mounted to the coupler mounting portion. The coupler includes an engaging claw which is adapted to engage the peripheral groove when the coupler is mounted to the coupler mounting portion and a releasing mechanism for disengaging the engaging claw from the peripheral groove when the coupler is detached from the coupler mounting portion. The Linkage mechanism engages the releasing mechanism when the cylinder is mounted to the cart.
The demand regulator may comprise a passage extending between the inlet port and the outlet port, pressure regulating means provided in the passage, a flow regulating means provided downstream of the pressure regulating means and a supply controlling unit, provided downstream of the flow regulating means, for fluidly connecting the outlet port to the inlet port when the patient is in the inspiration phase to supply the respiratory gas to the patient.
The supply controlling unit preferably comprises an inspiration sensor for detecting inspirations of the patient, a solenoid operated valve for fluidly connecting and disconnecting the inlet port and the outlet port and a solenoid driver circuit for opening the solenoid operated valve when the inspiration sensor detects the inspiration of the user.
An electric power source device for driving the solenoid of the solenoid operated valve may be provided in the respiratory gas supplying apparatus and the demand regulator may further comprise a pressure sensor for detecting the pressure in the passage. In this case, the demand regulator activates the electric cower source when the pressure in the passage increases to a predetermined high level and deactivates the electric power source device when the pressure in the passage decrease to the predetermined low level.
The shut-off valve attach to the cylinder may comprise a solenoid operated valve. The demand regulator may comprises a solenoid driver circuit for driving the solenoid of the solenoid operated driver, an electric power source device and a switch for opening and closing the shut-off valve through the solenoid driver circuit.